Re: [PATCH 2/2] Compute traceframe usuage per tracepoint on demand.

[Pedro Alves <palves@redhat.com>]

On 12/17/2012 09:20 AM, Yao Qi wrote:
> On 12/12/2012 09:37 AM, Yao Qi wrote:
>> +  /* Compute the traceframe usage of tracepoint whose number is
>> +     NUM.  */
>> +  for (tframe = FIRST_TRACEFRAME ();
>> +       tframe->tpnum != 0;
>> +       tframe = NEXT_TRACEFRAME (tframe))
>> +    if (tframe->tpnum == num)
>> +      traceframe_usage += tframe->data_size;
>> +
>>     sprintf (own_buf, "V%" PRIu64 ":%" PRIu64 "", tpoint->hit_count,
>> -       tpoint->traceframe_usage);
>> +       traceframe_usage);
> 
> It is incorrect for tracepoint with multiple locations, because multiple tracepoints in GDBserver have the same tracepoint number, and each tracepoint has its own traceframe usage.
> 
> On 12/12/2012 09:37 AM, Yao Qi wrote:
>> Then, I thought that we may use pointer to
>> 'struct tracepoint' instead of tracepoint num in 'struct traceframe',
>> but comments of 'struct traceframe' tell me that I shouldn't do this,
>> "This object should be as small as possible".  If we don't mind
>> increasing 2 bytes (on 32-bit target) for each 'struct traceframe',
> 
> Looks we have to go this way, in order to get the correct traceframe usage of each tracepoint in GDBserver.

To avoid the size penalty on 64-bit, another option would be
for gdbserver to maintain an internal tracepoint number, unique
for each location, and for traceframes to record that instead
of gdb tracepoint number.

Did you try the other option of accounting for usage in
add_traceframe_block?  I suspect it may be simple and not
add much more than a few instructions.

> I'll post a new patch again.

I may have missed it.  Have you posted it?

-- 
Pedro Alves